Trial for new intraocular lens power calculation following phototherapeutic keratectomy

PURPOSE

To determine an equation to calculate the intraocular lens (IOL) power for eyes that have undergone laser phototherapeutic keratectomy (PTK).

METHODS

The Gullstrand series was used to determine the power and radius of curvature of a convex-plane IOL, which will alter the focal point from the cornea to the conjugate point on the retina using the ray tracing method.

RESULTS

The radius of curvature of the anterior corneal surface (R), axial length (AXL), the predicted postoperative anterior chamber depth (ACD), and lens thickness (LT) were used in the following formula to calculate the refractive power of the IOL to be used: K = R/7.7, DC = 337.5/R, VC = lOOO/DC x 1.336 where VC is the posterior vertex focal length, A(1) = -(VC - ACD), B(1) = AXL - 0.5 x K - ACD - 0.103LT, S = l/A(1) + l/B(1), K is the proportional expression for anterior corneal curvature, DC = anterior corneal refractive power, A(1) = distance from anterior surface of IOL to posterior vertex focal point, B(1) = distance from the second principal point of IOL to the retina, S = 1/focal length of IOL in air. Using this equation, the power (in diopters) of the IOL in liquid was determined to be 1000/(l/S). 1. 336. In eyes that have undergone PTK, the keratometric value prior to cataract surgery is not used. Instead a value, R', is introduced. R' is defined as (R - 376/1376. dT), where R is the radius of corneal curvature prior to PTK and dT the amount of corneal tissue removed. The corneal thickness after cataract surgery, CT', was defined as CT - dT, where CT is the corneal thickness prior to PTK.

CONCLUSION

The new equation appears to be useful for determining the IOL power, although it is important to select a lens that has the accurate predicted anterior chamber depth.

Aurine tricarboxylic acid, a potent metal-chelating inhibitor of NFkappaB-DNA binding

The metal-interaction of aurine tricarboxylic acid (ATA) and its inhibitory effect on the DNA binding of NFkappaB were studied. Chemical speciation and spectroscopic studies have shown the strong interaction of ATA with metal ions present in the biological systems. EPR, FTIR and electronic spectral studies indicated the square planar structure of the metal-binding carboxylic and hydroxyl groups of ATA indicating the ground state 2B1g. Electrophoretic mobility shift assay using NFkappaB and 32P labeled DNA has shown that ATA was inhibitory against the DNA-NFkappaB binding at 30 microM. This activity was the strongest among the metal-chelating inhibitors of NFkappaB-DNA binding reported so far.

Specific impairment of cardiogenesis in mouse ES cells containing a human chromosome 21

Down syndrome (DS) leads to cardiac defects which are common and significant in babies with DS. We recently generated chimeric mice carrying a human chromosome (hChr) 21. The contribution ratio of embryonic stem (ES) cells containing a hChr 21 was specifically low in the heart, compared to other organs, and cardiovascular malformations were observed, suggesting that an additional copy of hChr 21 also disrupts the normal development of heart in mice. Here we describe that the presence of hChr 21 in ES cells delays the appearance of beating cardiomyocyte during differentiation, whereas differentiation into other cell types is not disrupted. Furthermore, the defect in cardiogenesis was restored following the deletion of a specific region of hChr 21. Therefore, we conclude that the imbalance of specific gene(s) on hChr 21 may lead to the disturbance of cardiogenesis and that this may be a useful system to model and investigate the cardiac defects of human DS.

Synthesis of NF-kappaB activation inhibitors derived from epoxyquinomicin C

In order to develop new inhibitors of NF-kappaB activation, we designed and synthesized dehydroxymethyl derivatives of epoxyquinomicin C, namely, DHM2EQ and its regioisomer DHM3EQ. These derivatives were synthesized from 2,5-dimethoxyaniline in 5 steps. Since DHM2EQ was more active and less toxic than DHM3EQ, its stereochemical configuration was determined by X-ray crystallographic analysis. Each enantiomer of the protected DHM2EQ was separated by a chiral column and deprotected. DHM2EQ inhibited TNF-alpha-induced activation of NF-kappaB in human T cell leukemia cells, and also inhibited collagen-induced arthritis in a rheumatoid model in mice.

Transcriptional regulation of the ATP citrate-lyase gene by sterol regulatory element-binding proteins

In an attempt to identify unknown target genes for SREBP-1, total RNA from a stable Chinese hamster ovary cell line (CHO-487) expressing a mature form of human SREBP-1a (amino acids 1-487) with a LacSwitch Inducible Mammalian Expression System was subjected to a polymerase chain reaction subtraction method. One of the fragments was found to have 90 and 86% homology with rat and human ATP citrate-lyase (ACL) cDNA, respectively. When Hep G2 cells are cultured under either sterol-loaded or -depleted conditions, expression of the gene is induced approximately 2-3-fold by sterol depletion. To investigate the direct effect of SREBP-1a on transcription, luciferase assays using the promoter of the human ACL gene were performed. These deletion studies indicated that a minimum 160-base pair segment contains the information required for the transcriptional regulation brought about by enforced expression of SREBP-1a. Luciferase assays using mutant reporter genes revealed that SREBP-dependent transcriptional regulation is mediated by two nearby motifs, the SREBP-binding site (a TCAGGCTAG sequence) and the NF-Y-binding site (a CCAAT box). It was confirmed by gel mobility shift assays that recombinant SREBP-1a binds to the sequence. Data from studies with transgenic mice and reporter assays show that the ACL gene promoter is activated by SREBP-1a more strongly than SREBP-2 in contrast to the HMG CoA synthase and LDL receptor gene promoters, which exhibit the same preference for the two factors. Therefore, SREBPs transcriptionally regulates ACL enzyme activity, which generates the cytosolic acetyl CoA required for both cholesterol and fatty acid synthesis.

Magnetoresistance of ferromagnetic tunnel junctions in the double-exchange model

We conduct a theoretical study of the temperature dependence of the spin polarization ( P) and the magnetoresistance (MR) ratio using the double exchange (DE) model for ferromagnetic tunnel junctions with half-metallic systems. It is shown that the strong exchange coupling in the DE model plays an important role in the temperature dependence of both P and the MR ratio; their values can be less than the maximum values expected for half-metallic systems at low temperatures, and the MR ratio decreases more rapidly than P with increasing temperature. The calculated results, however, indicate that the MR ratio may still be large at high temperatures near the Curie temperature.

Ovarian leiomyosarcoma: an autopsy case report

Primary non-specific sarcoma of the ovary is extremely rare, and only 22 reported cases of pure leiomyosarcoma (LMS) are known to the authors. We present an autopsy case of a primary ovarian leiomyosarcoma in a 73-year-old woman. She had noticed an abdominal mass after difficulty in defecating for several months. The excision of tumor with bilateral salpingo-oophorectomy and hysterectomy was carried out. A diagnosis of pure leiomyosarcoma of the left ovary was made on pathological examination with immunohistochemistry. Adjuvant radio-chemotherapy was not given. At 18 months' follow up, abdomino-pelvic sonography revealed an abdominal tumor and hepatic metastasis. The patient died 3.5 years after the initial surgery. The post-mortem examination revealed a peritoneal recurrent tumor and extensive distant metastases of the liver, lungs, pancreas, gastric mucosa, muscle and skin. The prognosis of the ovarian LMS is poor from the pertinent literature. Several prognostic indicators on histology including mitotic activity, proliferative activity and p53 status of the tumor are discussed.

Immunomodulatory effect of a plasmid expressing CD40 ligand on DNA vaccination against human immunodeficiency virus type-1

CD40 ligand is a costimulatory molecule which acts a potent immunomodulator. We found the mice inoculated with human CD40 ligand expression plasmid (pMEhCD40L) combined with human immunodeficiency virus type-1 (HIV-1) DNA vaccine exhibited both humoral and cellular antigen-specific immunological enhancement. The expression of hCD40L induced predominantly antigen-specific immunoglobulin G (IgG) antibody response while it failed to induce mucosal IgA response. Delayed-type hypersensitivity (DTH) and cytotoxic T lymphocyte (CTL) activity were induced in a dose-dependent manner. Examination of the relative levels of the two IgG subclasses showed that co-injection of pMEhCD40L enhanced IgG2a response without suppressing IgG1 response. Similarly, the expression of pMEhCD40L enhanced not only T helper 1 (Th1)- but also Th2-type cytokine production. In conclusion, co-inoculation of pMEhCD40L with DNA vaccine was shown to be a useful way to enhance CTL responses without suppressing the humoral immune response in acquired immune deficiency syndrome (AIDS) patients.

Sterol regulatory element-binding protein negatively regulates microsomal triglyceride transfer protein gene transcription

We herein report that mRNA expression of microsomal triglyceride transfer protein (MTP) and its protein synthesis decline in response to sterol depletion in HepG2 cells, and we functionally characterized the MTP gene promoter in an effort to investigate the molecular mechanisms by which MTP gene transcription is regulated. Luciferase assays using truncated versions of the reporter gene revealed that the region at -124 to +33 base pairs of the human promoter contains the elements required for the suppression of transcription by sterol depletion. Enforced expression of an active form of sterol regulatory element-binding protein (SREBP)-1 (amino acids 1-487) or -2 (amino acids 1-481), both of which are activated under sterol-depleted conditions, is able to mimic sterol-mediated down-regulation. Either further truncation of the promoter region or mutation of the putative SREBP-binding sequence (5'-GCAGCCCAC-3', -124 to -116 base pairs) abolishes the sterol- and SREBP-dependent transcriptional regulation. Gel mobility shift assay showed that recombinant SREBP-2-(1-481) is able to bind the sequence. Enforced expression of a truncated form of SREBP-2 (amino acids 31-481), which acts as an inhibitor of transcription of the low density lipoprotein receptor gene because it lacks the transcriptional activation domain, also diminishes the luciferase activity, suggesting that direct binding to the promoter region might be sufficient and that the mechanism by which SREBPs inhibit MTP gene expression is distinct from that for the transcriptional stimulation of sterol-regulated genes. Although the SREBP-binding site overlaps a negative insulin-responsive element, insulin negatively regulates MTP gene expression even when the amount of the active form of SREBPs is quite low under the sterol-loaded conditions, indicating that SREBPs only slightly mediate, if at all, the insulin effects. Overall, we conclude that SREBPs are responsible for regulation of lipoprotein secretion via their control of MTP gene expression. Moreover, our results describe for the first time a novel mechanism by which SREBPs negatively regulate expression of the gene encoding the protein involved in lipid metabolism.

Presence of phospholipid-neutral lipid complex structures in atherosclerotic lesions as detected by a novel monoclonal antibody

A novel monoclonal antibody (ASH1a/256C) that recognizes atherosclerotic lesions in human and Watanabe heritable hyperlipidemic (WHHL) rabbit aortae is described. When (123)I-labeled ASH1a/256C antibody is injected intravenously into WHHL rabbits, it associates specifically with fatty streaks on the aorta. The antigen recognized by the antibody is lipid, based on extraction with chloroform and methanol from WHHL rabbit tissues. The antigen, purified by high performance liquid chromatography, was shown to be phosphatidylcholine (PC), which contains unsaturated fatty acyl groups based on analyses utilizing (1)H and (13)C nuclear magnetic resonance, Fourier transfer-infrared spectrum, and mass spectrometry. The antibody did not react with other classes of phospholipids or neutral lipids when tested using an enzyme-linked immunosorbent assay. When PC was mixed with either cholesterol, cholesteryl ester, or triacylglycerol, however, the reactivity of the antibody to PC increased up to 8-fold. Homogenates of aorta tissue obtained from normal and WHHL rabbits were fractionated using sucrose density gradient ultracentrifugation in which neutral lipid droplets, cellular membranes, and proteins are separated. The phospholipid content in cellular membrane fractions from WHHL rabbits was twice as high as that of normal rabbits, and there was an enormous difference in the antigenic activity in these fractions. The content of cholesterol in the cellular membrane fraction of WHHL rabbits was approximately 50 times higher than that of normal rabbits. Addition of neutral lipids to the cellular membrane fraction of normal rabbit markedly increased the antigenic activity. Atheromatous lesions in thickened WHHL rabbit aortic intima that were rich in lipid droplets were stained positively with ASH1a/256C immunohistochemically. These results strongly suggest that PC-neutral lipid complex domains are formed in atherosclerotic lesions.

IKK-i, a novel lipopolysaccharide-inducible kinase that is related to IkappaB kinases

Using the suppression subtractive hybridization technique, we isolated a novel kinase, IKK-i, whose message is drastically induced by lipopolysaccharide (LPS) in the mouse macrophage cell line RAW264. 7. The predicted protein contains the kinase domain in its N-terminus, which shares 30% identity to that of IKK-alpha or IKK-beta. The C-terminal portion contains a leucine zipper and a potential helix-loop-helix domain, as in the case of IKK-alpha and IKK-beta. IKK-i is expressed mainly in immune cells, and is induced in response to proinflammatory cytokines such as tumor necrosis factor-alpha, IL-1 and IL-6, in addition to LPS. Overexpression of wild-type IKK-i phosphorylated serine residues Ser32 and Ser36 of IkappaB-alpha (preferentially Ser36), and significantly stimulated NF-kappaB activation. These results suggest that IKK-i is an inducible IkappaB kinase which may play a special role in the immune response.

Syntheses and SH-enzyme inhibitory activities of new epoxysuccinic acid piperazine derivatives against mu-calpain and cathepsin B

New chiral epoxysuccinic acid derivatives 5 approximately 23 bearing various amino acids and N-substituted piperazines were synthesized to evaluate their inhibitory activities against mu-calpain and cathepsin B. After screening these compounds, 1-[(2S,3S)-epoxysuccinyl-L-leucyl]-4-(2-chlorophenyl)piperazine 9 proved to exhibit fairly strong inhibitory activity against both cysteine proteases. L-Valyl derivative 19 exhibited selective inhibitory activity against cathepsin B in comparison with that against mu-calpain.

Regulatory role of metallothionein in NF-kappaB activation

Metallothionein (MT), a low molecular weight, cysteine-rich metal binding protein, has been associated with cytoprotection from heavy metals and cellular oxidants. As MT has the ability to scavenge hydroxyl radicals, MT may control intracellular redox status. In the present study, we examined whether MT regulates the activity of nuclear factor-kappaB (NF-kappaB), which is one of the redox-regulated transcription factors, using the MT null embryonic cell lines established from MT null mice. We first found that tumor necrosis factor (TNF)-induced activation of the binding of NF-kappaB protein to DNA in wild type MT+/+ cells was lower than that in MT-/- cells. The NF-kappaB activation in MT-expressing cells established from MT-/- cells by the transfection of mouse MT-1 gene was also significantly lower than that in MT-/- cells. In addition, transfection of the MT gene inhibited TNF-induced IkappaB degradation and suppressed NF-kappaB-dependent gene expression induced by TNF. These results demonstrate that MT may function as a negative regulator of NF-kappaB activity.

Severe osteopetrosis, defective interleukin-1 signalling and lymph node organogenesis in TRAF6-deficient mice

BACKGROUND

TRAF6, a member of the tumour necrosis factor receptor-associated factor family, was first identified as a transducer of CD40 and interleukin-1 receptor (IL-1R) signals based on the interaction of TRAF6 with the cytoplasmic tail of CD40 and with the IL-1R associated kinase in vitro. However, the functions of TRAF6 in vivo remain unidentified.

RESULTS

We show that TRAF6-/- mice exhibit severe osteopetrosis and are defective in osteoclast formation. In vitro culture experiments revealed that osteoclast precursor cells derived from TRAF6-/- mice are unable to differentiate to functional osteoclasts in response to osteoclast differentiation factor (ODF). In bone marrow of TRAF6-/- mice, the number of sIgM+B220+ immature B cells is markedly reduced while the ratio of proB to preB cells is not affected. In contrast, development of thymocytes is not affected. Furthermore, TRAF6-/- mice are defective in lymph node organogenesis and IL-1 signalling in thymocytes.

CONCLUSIONS

The results identify TRAF6 as an essential component of ODF signalling pathway, and also show that TRAF6 plays pivotal roles in immune and inflammatory systems in vivo.

The kinase TAK1 can activate the NIK-I kappaB as well as the MAP kinase cascade in the IL-1 signalling pathway

Interleukin-1 (IL-1) is a proinflammatory cytokine that has several effects in the inflammation process. When it binds to its cell-surface receptor, IL-1 initiates a signalling cascade that leads to activation of the transcription factor NF-kappaB and is relayed through the protein TRAF6 and a succession of kinase enzymes, including NF-kappaB-inducing kinase (NIK) and I kappaB kinases (IKKs). However, the molecular mechanism by which NIK is activated is not understood. Here we show that the MAPKK kinase TAK1 acts upstream of NIK in the IL-1-activated signalling pathway and that TAK1 associates with TRAF6 during IL-1 signalling. Stimulation of TAK1 causes activation of NF-kappaB, which is blocked by dominant-negative mutants of NIK, and an inactive TAK1 mutant prevents activation of NF-kappaB that is mediated by IL-1 but not by NIK. Activated TAK1 phosphorylates NIK, which stimulates IKK-alpha activity. Our results indicate that TAK1 links TRAF6 to the NIK-IKK cascade in the IL-1 signalling pathway.

Two differently regulated nuclear factor kappaB activation pathways triggered by the cytoplasmic tail of CD40

CD40 signaling modulates the immune response at least in part by activation of nuclear factor kappaB (NFkappaB). It has been shown that two distinct domains in the CD40 cytoplasmic tail (cyt), namely cyt-N and cyt-C, independently activate NFkappaB. Although four members of the tumor necrosis factor receptor-associated factor (TRAF) family, including TRAF2, TRAF3, TRAF5, and TRAF6, bind to the CD40 cyt, how each TRAF protein contributes to the NFkappaB activation by CD40 is not clear. Here we report that TRAF2, TRAF3, and TRAF5 bind cyt-C, whereas TRAF6 binds cyt-N. cyt-N is conserved poorly between human and mouse CD40, while cyt-C is highly conserved. However, single aa substitution of Glu-235 in cyt-N of human CD40 with Ala abolishes the binding of TRAF6 to cyt-N and NFkappaB activation by cyt-N. Conservation of this Glu between mouse and human CD40 strongly suggests that TRAF6 could link cyt-N to signals essential for CD40-mediated immune response. Furthermore, NFkappaB activation by cyt-C is inhibited by a kinase-negative form of NFkappaB-inducing kinase more efficiently than that by cyt-N, consistent with the result that NFkappaB activation by TRAF2 and TRAF5 is inhibited by a kinase-negative form of NFkappaB-inducing kinase more efficiently than that by TRAF6. These results indicate that NFkappaB activating signals emanating from cyt-N and cyt-C are mediated by the different members of the TRAF family and could be regulated in a distinct manner.

A novel splicing isoform of mouse sterol regulatory element-binding protein-1 (SREBP-1)

We cloned a cDNA encoding the NH2-terminal portion of mouse SREBP-1. The deduced amino acid sequence was 76% and 90% identical to human and hamster SREBP-1, respectively. We found out a novel splicing isoform of mouse SREBP-1 that lacks 42 amino acid residues composing a PEST sequence observed in unstable proteins. It has been reported that SREBP-1 is rapidly turned over in the nucleus. Although this isoform was not a dominant isoform, it might be possible that the produced protein functions differently from other isoforms including a complete PEST sequence.

Simultaneous analysis of microheterogeneity of immunoglobulins and serum protein fraction using high-voltage isoelectric focusing on six cellulose acetate membranes

A systematic detection method for the single performance of cellulose acetate (CA) membrane isoelectric focusing to detect six different types of information on protein abnormalities was developed. High-voltage isoelectric focusing was carried out on six layers of CA membrane using a thermoelectric cooling apparatus. After electrophoresis, the proteins on the top, the third, the fourth, the fifth, and the bottom CA membrane were transferred to a polyvinylidene difluoride (PVDF) membrane by a simple contact printing procedure to detect IgM, kappa-chain, lambda-chain, IgA, and IgG, respectively. Each PVDF membrane revealed the microheterogeneity of these immunoglobulins using specified anti-serum and enzyme immunostaining. The second CA membrane was stained with Coomassie brilliant blue G250 to detect serum protein patterns. All stained membranes showed clear electrophoretic patterns of immunoglobulin microheterogeneity. By our method, immunoglobulin abnormalities in serum could be screened out using six different types of information obtained simultaneously.

Oligonucleotides bearing 5-formyl-2'-O-methyluridine: preference in binding affinity to the NF-kappa B (p50)2 homo- and p50/p65 heterodimers

5-Formyl-2'-O-methyluridine was incorporated into the various positions of oligonucleotide 26-mers containing the NF-kappa B binding sequence. Some of them showed binding selectivity toward the homo- and heterodimers of subunits of NF-kappa B.

Molecular analysis of constitutive IL-1alpha gene expression in human melanoma cells: autocrine stimulation through NF-kappaB activation by endogenous IL-1alpha

Constitutive production of/and acquired resistance to anti-proliferative cytokines are implicated in pathogenesis and progression of human melanoma cells. Human melanoma cells A375-C6 are sensitive to interleukin 1 (IL-1) anti-proliferative effect and do not produce IL-1. After long period of culture we have obtained cells which acquired resistance to IL-1. The resistant cells exhibited constitutive production of IL-1α. To analyse the mechanisms that lead to the expression of IL-1α in the cells, we transfected of the resistant clone A375-R8 with CAT (chloramphenicol acetyltransferase) expression plasmids linked to a 5'-flanking deletion mutants of the human IL-1α gene. Two nucleotide regions (--103 to --70 bp) and (--70 to --47 bp) from the start of the first exon appeared to contain a positive regulatory element(s) while the one --421 to --103 bp contained a negative regulatory element(s).The --103 to --70 bp region contained the consensus NF(-k)B (nuclear factor-kB) binding motif.(Immunofluorescence analysis revealed that NF-kB is activated in A375-R8 cells. IL-1 receptor antagonist (IL-1Ra) decreased the level of IL-1α mRNA and production of IL-1α. IL-1Ra also inhibited the localization of p65 in the nuclei and CAT activity in transfectants with the plasmids containing NF-kB binding motif. These results indicate that endogenous IL-1α stimulates the gene expression and production of IL-1α in an autocrine manner through activation of NF-kB.

Interactions between NFkappaB and its inhibitor ikappaB: biophysical characterization of a NFkappaB/ikappaB-alpha complex

The N-terminal domain (1-318 amino acids) of mouse NFkappaB (p65) has been purified to homogeneity from the soluble fraction of Escherichia coli cells expressing this protein. Its complex with a full-length ikappaB-alpha (MAD3, 1-317 amino acids) molecule was generated by binding the E. coli-derived ikappaB-alpha to the purified NFkappaB and purifying the complex by sequential chromatography. The stoichiometry of NFkappaB to ikappaB in the complex was determined to be 2 to 1 by light scattering and SDS-polyacrylamide gel electrophoresis. The secondary structure of the NFkappaB (p65) determined by Fourier-transform infrared (FTIR) spectroscopy is in good agreement with that of the p50 in the crystal structure of the p50/DNA complex, indicating that no significant structural change in NFkappaB occurs upon binding of DNA. The FTIR spectrum of the NFkappaB/ikappaB complex indicates that its secondary structure is composed of 17% alpha-helix, 39% beta-strand, 18% irregular structures, and 26% beta-turns and loops. By comparing these data to the FTIR data for NFkappaB alone, it is concluded that the ikappaB (MAD3) in the complex contains 35% alpha-helix, 27% beta-strand, 22% irregular structures, and 16% beta-turns and loops. Circular dichroism (CD) analysis of a shorter form of ikappaB (pp40) indicates that it contains at least 20% alpha-helix and that the ikappaB subunit accounts for nearly all of the alpha-helix present in the NFkappaB/ikappaB complex, consistent with the FTIR results. The stabilities of NFkappaB, ikappaB, and their complex against heat-induced denaturation were investigated by following changes in CD signal. The results indicate that the thermal stability of ikappaB is enhanced upon the formation of the NFkappaB/ikappaB complex.

[Trial of new intraocular lens power calculation following phototherapeutic keratectomy]

We reviewed the SRK-II method and introduce a new equation to calculate the intraocular lens (IOL) power for eyes which underwent laser phototherapeutic keratectomy (PTK). The Gullstrand series was used to determine the power and the radius of curvature of planoconvex IOLs which alter the focal point from the cornea to reach the conjugate point on the retina. The radius of anterior corneal curvature (R), axial length (AXL), predicted postoperative anterior chamber depth (ACD), and lens thickness (LT) were employed in the following formula to calculate the IOL refractive power: K = R/7.7, DC = 337. 5/R, VC = 1,000/DC*1.336 where VC is the posterior vertex focal length. A1 = -(VC-ACD), B1 = AXL-0.5* K-ACD-0. 103 LT, S = 1/A1 + 1/B1; this determined the diopter (D) of IOL in liquid to be (D) = 1,000/(1/S)* 1.336. In eyes which underwent PTK, the keratometric value prior to cataract surgery was not applied. Instead, R' defined as R-dT, where R is the radius of corneal curvature prior to PTK and dT the amount of corneal tissue removed, was introduced. Further, the corneal thickness before cataract surgery (CT') was defined as CT-dT where CT is the corneal thickness prior to PTK. Although it is important to select a lens that has an acurate predicted anterior chamber depth, the new equation appears to be more useful than the SRK-II formula.

Induction of apoptosis in human pancreatic carcinoma cells by a synthetic bleomycin-like ligand

Histidine-pyridine-histidine-3 (HPH-3) is an oxygen-activating ligand based on the structure of bleomycin. HPH-3 induced the death of human pancreatic adenocarcinoma AsPC-1 cells in 24 h, causing apoptotic morphology and internucleosomal degradation of DNA. HPH-3-induced cell death was not inhibited by antioxidants such as reduced glutathione and N-acetylcysteine, whereas hydrogen peroxide-induced cell death was inhibited by them, indicating that hydrogen peroxide is not involved in the induction of apoptosis by HPH-3. Induction of apoptosis by HPH-3 was inhibited by zinc and copper ions, indicating that chelation with ferrous ion is responsible for induction of apoptosis, as is the case in chelation by bleomycin to cleave DNA. Bleomycin A2 and its fragment having no DNA-binding region, glycopeptide-3, did not induce apoptosis in AsPC-1 cells. Bleomycin A2 induced G2/M block in flow-cytometric analysis, but HPH-3 did not and instead induced an apoptotic pre-G1 peak. Thus, HPH-3 induced apoptosis in human pancreatic carcinoma cells, which is a unique characteristic among bleomycin-related compounds.